by Brett Kelman, USA TODAY

by Brett Kelman, USA TODAY

PALM SPRINGS, Calif. -- A series of ambushes and gunfights killed as many as three people and seriously wounded another last week in a mountainous region just south of the U.S-Mexico border.

The shootings, involving masked gunmen and undocumented immigrants, occurred over a two-day span, prompting an investigation from an international law enforcement team, according to the U.S. Customs and Border Protection.

"We just want to make sure that people realize the dangers of crossing through the desert, especially through areas that are remote like that," said Supervisory Agent Fabian Morales, a Border Patrol spokesman. "People need to understand."

According to a Border Patrol news release, the first ambush occurred on Feb. 16, when a group of five immigrants was robbed by two masked men, armed with rifles, as they sneaked through the mountains west of Calexico, a border town in California. As the immigrants were held by the masked men, a separate group of gunmen confronted the immigrants and the masked men, attempting to rob the entire group, sparking a gunfight.

As the robbers fought amongst themselves, the immigrants fled north into the U.S., where they were arrested by the Border Patrol.

Mexican authorities were notified of the gunfight and recovered several expended shotgun rounds from the scene. Although the group of immigrants said one gunman was killed in the firefight, Mexican authorities found no bodies at the scene, the news release states.

The second ambush occurred a day later, when a group of eight immigrants was robbed by gunmen with rifles in the same area. The immigrants said they were held captive for several hours but were able overpower their captors, killing two of the them. Authorities later found the bodies.

One of the immigrants was shot in the face during the gun battle, so the immigrants rushed north, calling 911 after they had crossed the border.

The wounded man was flown to Palm Springs for medical attention. He was in serious but stable condition Wednesday, Morales said.

The Border Patrol has teamed with the Department of Homeland Security and Mexican authorities to investigate both reports. The investigation resulted in the recovery of one ski mask, one AK-47 and one Ruger .223 rifle and two large-capacity magazines, according to a news release.

Morales said authorities had little hope of finding the surviving bandits, who disappeared into a quagmire of mountain caves, canyons and other hiding spots.